The used oak barrels are milled with a CNC-controlled high-pressure water jet on the inside. The water jet is generated by a pump at a pressure of more than 3500 bar and makes the speed of sound on the surface of the drum wall. The thickness of the removed wood layer can be precisely adjusted by varying process parameters. The actual removal process is largely automatic.
The cutout of used wooden barrels carried out without disassembly of the barrel.
The system used consists of a high pressure pump, a drum manipulator, a cleaning system and a documentation unit.
The water jet is guided with CNC – controlled nozzle over the entire inner surface of the barrel.
In the nozzles integrated probes allow the accurate recording of the barrel geometry. From the obtained measured values, the CNC program is calculated for the machining operation.
The control of treatment of the inner barrel surface is carried out with optical methods.
By the gradual erosion of the inside of the wooden barrel with the high pressure water jet arise structures that significantly increase the contact surface of barrel and wine. Thus, the mass transfer of wooden aromas is accelerated and intensified.
After the inner threatment the barrel is carefully cleaned outside. Red wine stains and dirt are largely removed by grinding.
The finished oak barrels can be toasted on request.
Since the toasting process is no longer required for shaping the staves in the barrel manufacturing, reconditioned drums can be supplied without toasting and can be used to produce white wines also. In that case, the finished barrel is thermally sterilized before delivery.
Own method was developed for toasting a reconditioned barrel. Heated gas at high speed is circulating inside the barrel. Due to the high gas velocity, the gas temperature can be kept very close to the required toast temperature, and the often seen overheating when using conventional processes can be avoided. With the time control is also possible to influence on the depth of the toasting into the barrel wall.
Since the gas temperature can be accurately controlled, it is possible to set the desired toast degree accurately and reproducibly. Gas temperature and the temperature of the barrel inner wall  are measured during the entire toast process and can be documented by recording for each barrel.